Effect size (adjusted ORs) of smoking quality and CYP2A6 genotypes on hypertension stratified by both levels of daily cigarette consumption and CYP2A6 genotypes in 954 Chinese male current smokers. The group with smokers who consumed 1 - 15 cigarettes per day and CYP2A6 slow metabolizer genotype was the reference group (OR=1). The adjusted variables were age, education level, physical exercise, alcohol consumption, family history of hypertension, BMI and WHR. N, CYP2A6 normal metabolizer genotype; I, CYP2A6 intermediate metabolizer genotype; S, CYP2A6 slower metabolizer genotype.